Process for the preparation of polyesteroximes and polybenzoxazole (pbo) type polymers derived therefrom

ABSTRACT

Process for the preparation of polymers which comprises reacting at temperatures of from about 0* to about 250*C an aromatic diol or its alkali metal or Group IIa or IIb metal di-salt with a bis(hydroxamoyl halide) or a derivative thereof to form a polyesteroxime, which may then be subjected to ring closing conditions to form polybenzoxazole (PBO) type polymers. Formation of the polyesteroxime is preferably conducted in the presence of a solvent, which may or may not also function as an acidacceptor; if not, then preferably also in the presence of an acid-acceptor. The preferred acid-acceptors are those which are insoluble in the reaction mixture- most preferably melamine. The ring closure may be conducted in the presence of a catalyst at temperatures of from about 0* to about 250*C or by reaction with a sulfonyl halide at temperatures of from about 0* to about 90*C. Reactive hydroxy or hydroxamoyl halide terminal groups of the polyesteroximes, or PBO type polymers, may be reacted with other compounds or polymers which contain groups reactive therewith in order to further extend the polymer chains. In a preferred prior step, aromatic bis(hydroxamoyl halide) reactants are made by the reaction of dialkyl aromatic precursors, e.g., any of the isomers of xylene, with, e.g., nitrosyl halide. Novel polyesteroximes.

United States Patent [191 Zellner et al.

[ Oct. 9, 1973 [75] Inventors: Carl N. Zellner, New Hope, Pa.;

Henry W. Steinmann, Sparta, NJ.

[73] Assignee: Celanese Corporation, New York,

[22] Filed: Oct. 30, 1970 [21] Appl. No.: 85,753

260/824 R [51] Int. Cl C08g 33/02 [58] Field of Search 260/47 R, 49, 79,

260/2 R, 2 S, 79.3 R

[56] References Cited UNITED STATES PATENTS 3,268,545 8/1966 Litt et al. 260/307 3,306,876 2/l967 Kantor et al....

3,560,438 2/l97l Burton et al 260/47 Primary Examiner-William H. Short Assistant ExaminerL. L. Lee Att0rneyThomas J. Morgan, C. B. Barris and K. E.

Macklin [57] ABSTRACT Process for the preparation of polymers which comprises reacting at temperatures of from about 0 to about 250C an aromatic diol or its alkali metal or Group [1a or Ilb metal di-salt with a bis(hydroxamoyl halide) or a derivative thereof to form a polyester-oxime, which may then be subjected to ring closing conditions to form polybenzoxazole (PBO) type polymers. Formation of the polyesteroxime is preferably conducted in the presence of a solvent, which may or may not also function as an acid-acceptor; if not, then preferably also in the presence of an acid-acceptor. The preferred acid-acceptors are those which are insoluble in the reaction mixturemost preferably melamine. The ring closure may be conducted in the presence of a catalyst at temperatures of from about 0 to about 250C or by reaction with a sulfonyl halide at temperatures of from about 0 to about 90C. Reactive hydroxy or hydroxamoyl halide terminal groups of the polyesteroximes, or PBO type polymers, may be reacted with other compounds or polymers which contain groups reactive therewith in order to further extend the polymer chains. In a preferred prior step, aromatic bis(hydroxamoyl halide) reactants are made by the reaction of dialkyl aromatic precursors, e.g., any of the isomers of xylene, with, e.g., nitrosyl halide. Novel polyesteroximes.

21 Claims, No Drawings PROCESS FOR THE PREPARATION OF POLYESTEROXIMES AND POLYBENZOXAZOLE (PBO) TYPE POLYMERS DERIVED THEREFROM This invention relates to a novel process for the preparation of polyesteroximes and to polybenzoxazole (PBO) type polymers produced therefrom.

Polyesteroximes are useful as chelating agents for sequestering polyvalent metal ions in plating baths, polluted streams, etc. The polymers are also useful as catalyst carriers and as ion-exchange resins. The polymers may be formed into fibers, films. molded articles, etc. Instead of undergoing ring closure to form the PBO type polymers of this invention, the polyesteroximes may be hydrolyzed to high performance polyesters by reaction with, e.g., dilute hydrochloric acid, or their oxime groups may be hydrogenated under appropriate conditions to amine groups to form polyamines, which are also useful as chelating agents. The polyamines may be reacted with polyepoxides to form epoxy resins and moded articles, or they may be cross-linked with dicarboxylic acids to form polyamide resins of interesting and varied properties.

The PBO polymers of this invention generally are useful for applications where high performance polymers are required. For example, in aerospace applications where retention of strength at elevated temperatures and flame retardancy are required, the PBO polymers of this invention are outstanding. Heretofore, Nomex polyamide type resins have been used in coveralls, etc. worn by pilots and race car drivers to protect against injuries from fires resulting from crashes, etc. Unfortunately, Nomex garments are not as nonflammable as desired. In addition, wearers of these garments have complained that they are clammy, especially when worn in a closed cockpit. PBO type polymers are much less flammable than Nomex resins. Garments made from PBO type polymers are not clammy, especially when the fabric in the garment is woven from staple, which fabric has the feel of cotton.

Heretofore, PBO type polymers have been made by the reaction of an aromatic dihydroxy diamino compound with a dicarboxylic acid or a derivative thereof. Over-all this process is undersirable because it is expensive and also because of toxicity problems. The dihydroxy diamino compound is difficult to synthesize and difficult to purify, thereby resulting in a very expensive starting material. The other starting material is usually isophthaloyl chloride. PBO type polymers produced by the process of the prior art have been limited in applicability because of the tan color of the polymer. The PBO polymers of the present invention are white or nearly white. In any event, they are much lighter in color than the PBO type polymers of the prior art and may be dyed to almost any desired color.

One or more of the foregoing and other adverse effects of the prior art process are overcome by the novel process of the present invention.

Generally, the process of the present invention comprises reacting an aromatic dihydroxy compound with a bis (hydroxamoyl halide) or a derivative thereof to form the polycsteroxime, which may then be subjected to ring closing conditions to form the P80 type polymers of this invention.

Illustrative of the aromatic dihydroxy compounds or their alkali metal or Group Ila or Ilb metal di-salts which may be used in the present invention are those which may be depicted by the following general formula:

MOY-OM wherein M is hydrogen, or an alkali metal or Group Ila 0r metal; Y is ''C6H4-,c10H5, C14H3 ,Cg. H -,C I-I RC I-I.,, wherein R is as defined below, and the like. Y may be substituted with groups which do not detrimentally interfere with the reaction.

Illustrative subcategories of the hydroxy compounds which may be used are:

I. Compounds of the general formula MOZOM wherein M is as described above and wherein Z is C 4 l0 6' 14 s-;

II. Compounds of the general formula MOC H -C H OM wherein M is as described above; and

III. Compounds of the general formula MOC H R-C H OM wherein Mis as described above and R may be (ilglI C011 i, -Sii, Si, or thollko.

JJ a C2115 Calls In each of the above formulas, it is preferred that M be M, M being an alkali metal or a Group IIa or lIb metal. Preferred alkali metals are lithium, sodium and potassium. Preferred Group Ila and IIb metals are magnesium, strontium, barium, calcium and zinc. Sodium is most preferred as M, and sodium bisphenol A is the most preferred salt.

Illustrative or particular aromatic dihydroxy compounds which may be used in the process of this invention are the following:

1,2-dihydroxy benzene 1,3-dihydroxy benzene 1,4-dihydroxy benzene 1,4-dihydroxy naphthalene 1,5-dihydroxy naphthalene 1,6-dihydroxy naphthalene 1,7-dihydroxy naphthalene 1,8-dihydroxy naphthalene 2,3-dihydroxy naphthalene 2,6-dihydroxy naphthalene 2,7-dihydroxy naphthalene l,4-dihydroxy-2-methyl-naphthalene l,4-dihydroxy-anthracene 2,6-dihydroxy-anthracene 9, l O-dihydroxy-anthracene 9 l O-dihydroxy phenanthrene 2,2'-dihydroxy-biphenyl 2,4-dihydroxy-biphenyl 3 ,3 -dihydroxy-biphenyl 3,4'-dihydroxy-biphenyl 4,4-dihydroxy-biphenyl 4,4-dihydroxy-2,2-dimethyl-biphenyl l,l-bis(4-hydroxyphenyl) cyclohexane bis(4-hydroxyphenyl) dimethyl silane bis(4-hydroxyphenyl) diethyl silane bis(4-hydroxyphenyl)diphenyl silane bis(4-hydroxyphenyl) amine bis(4-hydroxyphenyl)ether,i.e., 4,4-dihydroxy diphenyl ether bis(4-hydroxyphenyl) thioether 2,2-bis(4-hydroxyphenyl) propane bis(4-hydroxyphenyl) sulfone bis(4-aminophenyl) sulfoxide bis(4-hydroxyphenyl) ketone bis(4-hydroxyphenyl) methane It is preferable to use the diols in the form of their disalts, rather than than the diols per se. Illustrative of the di-salts are the following:

disodium salt of l,2-dihydroxy benzene dipotassium salt of l,3-dihydroxy benzene disodium salt of 1,4-dihydroxy benzene dipotassium salt of 1,4-dihydroxy naphthalene disodium salt of l,5-dihydroxy naphthalene dipotassium salt of 1,6-dihydroxy naphthalene disodium salt of l,7-dihydroxy naphthalene dipotassium salt of 1,8-dihydroxy naphthalene disodium salt of 2,3-dihydroxy naphthalene dipotassium salt of 2,6-dihydroxy naphthalene disodium salt of l,4-dihydroxy-2-methyl-naphthalene dipotassium salt of 1,4-dihydroxy-anthracene disodium salt of 2,6-dihydroxy-anthracene dipotassium salt of 9,lO-dihydroxy-anthracene disodium salt of 9,10-dihydroxy phenanthrene dipotassium salt of 2,2-dihydroxy-biphenyl disodium salt of 2,4'-dihydroxy-biphenyl dipotassium salt of 3,3-dihydroxy-biphenyl disodium salt of 3,4-dihydroxy-biphenyl dipotassium salt of 4,4-dihydroxy-biphenyl disodium salt of 4,4-dihydroxy-2,2-dimethylbiphenyl dipotassium salt of l,l-bis(4-hydroxy phenyl) cyclohexane disodium salt of bis(4-hydroxy phenyl)dimethyl silane dipotassium salt of bis(4-hydroxy phenyl) diethyl silane ' disodium salt of bis(4-hydroxy phenyl) diphenyl silane dipotassium salt of bis(4-hydroxy phenyl) amine disodium salt of bis(4-hydroxy phenyl) ether, dipotassium salt of bis(4-hydroxy pheynl) thioether disodium salt of 2,2-bis(4-hydroxy phenyl) propane dipotassium salt of bis(4-hydroxy phenyl) sulfone disodium salt of bis(4-hydroxy phenyl) sulfoxide dipotassium salt of bis(4-hydroxy phenyl) ketone disodium salt of bis(4-hydroxy phenyl) methane By the term aromatic dihydroxy compound" is meant a compound in which the two hydroxy groups are each attached to an aromatic ring, not necessarily both attached to the same ring, however. Generally, any aromatic diol containing up to about 30 carbon atoms can be used in the present invention. Preferably the diol contains up to about 20 carbon atoms, most preferably up to about 15 carbon atoms. The most preferred diol is bis-phenol A.

Although the diol per se may be used in the reaction it is highly desirable to use the diol in the form of its alkali metal salt, especially its lithium, sodium or potassium salt. The sodium and potassium salts are preferred.

The alkali metal salts may be'formed by reacting, e.g., the alkali metal hydroxide with the aromatic diol in aqueous solution or suspension. It is preferred that the di-salt so formed be dried before use. The isolation and drying may be accomplished in any convenient and effective method which occurs to one skilled in the art. For example, the salt may be precipitated from solution by addition of an alcohol to the reaction mixture, the precipitate may be washed with ether and then dried in an oven. Alternatively, the reaction mixture may be dried to a slurry and then the remaining water azeotropically distilled with cyclohexanone or any other solvent with which water forms a useful azeotrope. These solvents are readily ascertained from available published tables of azeotropes.

Bis(hydroxamoyl halides) which may be used in this invention may be either aliphatic or aromatic and may be, e.g., the chlorides, bromides, or iodides. The chlorides and bromides are generally preferred. Derivatives of those compounds, e.g., the O-sulfonates, may be used instead. The compounds are illustrated by the following formula:

wherein X is halogen or-OR",-SR(R is alkyl of up to four carbon atoms) or -OC H R is a direct bond or a divalent aliphatic, aromatic or organosilicon group; and X is hydrogen or an -SO OK, --SO ONa,

(R" is alkyl of up to four carbon atoms),

Illustrative of the aliphatic groups represented by R are CH2 C2H4 C3H6 -C4Hg', and the like. Illustrative of the organo-silicon groups are andthe like. Illustrative of the aromatic groups represented by R are -C H.,-, C H -C I'I 1o e C, I-I (C l-I R, wherein Ris Ulla (lzllr, (lullg and the like. It is preferred that R be an aliphatic or aromatic divalent group. It is further preferred that R bly up to four carbon atoms. R is most preferably C Illustrative of particular bis (hydroxamoyl halides) are the following:

I ll lion 02m NOH i" IiOII NOH NOH II NOH ll I] OIIQCON NOCCH:

Generally, equimolar quantities of the reactants are used to form the polymers of this invention. However, it is possible to terminate the polymer chains with either hydroxamoyl halide groups or hydroxy groups merely by utilizing in the reaction an excess of the reactant containing either of those groups. To obtain relatvely high intrinsic viscosity polymers, it is generally preferred that the excess not exceed about mole percent.

When the polymer is terminated by hydroxamoyl halide groups, they may be reacted with compounds or polymers containing at least one group, preferably two groups, which is (are) reactive therewith under the conditions of the reaction. Such groups may be, for example, amines or phenoxides.

When an excess of the diol is used, the excess may function as chain-stoppers, or end-blocking units, the terminal hydroxy groups of which may serve as reactive groups through which the chain may be further extended by reaction with other compounds containing at least one group, preferably two groups, which is (are) reactive with they hydroxy groups under the reaction conditions. Such groups and compounds are, for example, hydroxamoyl halide; isocyanate; halogen, e.g., chlorine and bromine; epoxide; acid chlorides, e.g., adipoyl chloride, carboxy, e.g., adipic acid, tetracarboxy-naphthalene; SO CL phosgene (to form a carbonate linkage); or phosgenated diols (aliphatic or aromatic bis-chloro-carbonates [to form carbonate linkages]).

Of course, it will be obvious to one skilled in the art that mixed polymers may be produced by polymerizing more than one of either or each of the two reactants. These mixed polymers may be either random or alternating and may be formed from using mixtures of different species of either of both reactants, or they may be block polymers, which may be formed by reacting an hydroxy-terminated polymer of relatively low molecular weight with a hydroxamoyl halide-terminated polymer of relatively low molecular weight which has itself been formed from a diol or hydroxamoyl halide which is different from that used to form the first polymer. The relatively low molecular weight polymers may instead be substantially the same except for one being hydroxy-terminated and the other hydroxamoyl halideterminated, and possibly differences in molecular weight and configuration.

Cyclization of the polyesteroxime polymers may be accomplished before or after linking in the manner just described. If cyclization is to be performed before linking, the terminal hydroxy groups may need protection before cyclization is conducted. Protection may be ac .by-product hydrogen halide formed during the reaction.

Illustrative of the inert solvents which may be used are acetonitrile; nitrated solvents, e.g., nitromethane and nitrobenzene; chlorinated solvents, e.g., methylene chloride, chloroform, carbon tetrachloride, ethylene chloride, and chlorobenzene; N 0 the ethers, e.g., tetrahydrofurane,diethylether, and dioxane; the esters, e.g., amyl acetate, the lactones, e.g., butyrolact one, ketones, e.g., cyclopentanone and cyclohexanone; acetic acid; polyphosphoric acids; and cresols. Cyclohexanone and polyphosphoric acid are preferred.

If an inert solvent has been used, it is desirable to add to the mixture an acid-acceptor such as tertiary amine, e.g., trialkylamines such as trimethylamine, triethylamine, and the like; triethylene diamine; 1,3 dimethylamino butane; heterocyclic amines such as pyridine, picolines, lutidines; or an alkali metal or alkaline earth metal hydroxide, bicarbonate, carbonate, or alkanoate (up to four carbon atoms), e.g., sodium hydroxide, sodium carbonate, sodium bicarbonate, potassium acetate, etc.

Particularly useful acid-acceptors are those insoluble in the reaction mixture, e.g., melamine, phenylmelamine, dicyanamide, insoluble guanidine derivatives, insoluble basic ionexchange resins. Preferred are melamine and benzoguanamine. Of course, mixtures of the acid-acceptors may be used..The aforementioned acidacceptors may be used used in conjunction with the following solvents which also function as acid-acceptors.

Illustrative of the solvents which also function as acid-acceptors are dimethylacetamide (DMAc), di-

methylformamide (DMF), pyrrolidone, and its alkylated derivatives, e.g., N-methyl-pyrrolidone, dimethyl sulfoxide (DMSO), hexamethylphosphoramide, dialkylanilines, e.g., dimethylaniline and diethylaniline, and the like. DMAc is preferred.

In place of a single solvent in the reaction mixture there may be used mixed solvent systems containing either or both types of solvents.

In order to minimize undesirable side reactions, it is preferable to use either an acid-acceptor which is insoluble in the reaction mixture, preferable melamine, or to use a soluble amine, but ensure that its instantaneous concentration in the reaction mixture is relatively low, e.g., lower than 0.01 molar concentration for example, by slowly and continuously adding the acidacceptor or by incrementally adding small portions. Other ways of inhibiting undesirable side reactions are indicated in the schemata which follow.

The reaction of bis(hydroxamoyl halide)or a derivative with the aromatic diol in the presence of an acidacceptor is generally exothermic and may be conducted at autogenous temperature, or it may be conducted at a constant temperature by the application of the required cooling or heating conditions. The reaction may be conducted at temperatures of from about to about 250C.,preferably about 0 to about 100C. conditions, for exampl a g n reactor or one The closing of the ring to actually form the P80 type fabr cated from titan um or nickel. polymers may be accomplished by the appropriate To enable the reader to more easily visualize the thermal Conditions by heating the esteroxime steps of the invention, the following schemata are set Polymer to a temperature in the range of about to forth, using illustrative reactants. It will be readily apzsooc" preferably in the presence of a catalyst espe parent to the reader, however, that other reactants Gian) an acidic catalyst Such a Silica Silica mentioned throughout the specification and claims alumina, sulfonated polystrene ion-exchange resins, may be used in their Stead and polyphosphoric acid. Polyphosphoric acid is the preferred catalyst.

Ring closure may also be accomplished by the reac- PREPARATION OF ESTEROXIME POLYMER tion of the esteroxime polymer with sulfonyl halide, FROM BIS(HYDROXAMOYL CHLORIDE) or 01 CH3 HON NOI-I 3 such as benzene sulfonyl chloride, naphthalene sulfonyl CH3 chloride, toluene sulfonyl chloride, methane sulfonyl o b @-occhloride or other ring closing reagents under appropri- J ate conditions, e.g., about 0C. to about 90C. or L n higher, preferably about 5C. The aromatic sulfonyl halides are preferred. Toluene sulfonyl chloride is most Preferred PREPARATION OF POLYBENZOXAZOLE FROM The aromatic diols are either readily available or eas- ESTEROXIME POLYMER ily prepared by methods which are well-know to those skilled in the art. For example, 4,4'-dihydroxydiphenyl may be prepared by hydrolysis of 4,4-dihalodiphenyls.

The bis (hydroxamoyl halide), the other reactant in the novel process of this invention, may be prepared by @-c 3H HON several routes. For example, the appropriate aliphatic L n or aromatic dialdehyde, such as terephthalaldehyde or isophthalaldehyde may be reacted with hydroxylamine to form the corresponding bisoxime, which in turn may be reacted with halogen to form the bis (hydroxamoyl halide). Another method of preparing the bis (hydrox- CH amoyl halides) is to start with the appropriate dialkyl 4} 3 aromatic precursor, e.g., any of the isomers of xylene, which may be reacted with nitorsyl halide, preferably in the presence of additional halogen, to form the his L N N J (hydroxamoyl halides). Other reagents which may be used in place of the nitrosyl halide per se are a cornbination of nitric acid and hydrohalic acid, or a combina- PREPARATION OF BIS(HYDROXAMOYL tion of nitric oxide (NO) and halogen. CHLORIDE FROM XYLENE This second illustrative method, i.e., the reaction of NOCL XHzC@-CHX an appropriate dialkyl aromatic precursor, e.g., mxylene, with nitrosyl halide or any one of its aforementioned alternatives, is the preferred methods for the preparation of the bis (hydroxamoyl halides). This step in combination with the basic process of the invention, N H N i.e., the reaction of the bis (hydroxamoyl halide) with an aromatic diol results in a relatively simple, easy, rel- X" may be hydrogen or chlorine atively inexpensive, over-all process for the preparation Instead of p xylene used in the above illustration one of Polyesteroximes from readily available Starting may instead use another aromatic reactant correspondtel'ials- These Polyesteroximes y be converted to ing to the desired aromatic bis(hydroxamoyl halides) PBO type polymers by ring closure reaction. described above The Process for the Preparation of bis It is possible that a bis(hydroxamoyl halide) may dedroxam-oyl halides) T be conducted at temperatures 6 compose in the presence of certain acid-acceptors in fi g 't i fg gg f f fg gg 'fi gg gi g ggjg accordance with the following illustrative side reaction: the range of an atomsphere or more, e.g., up to about 10 atmospheres, preferably from about one to about 5 01 Cl atmospheres. In view of the corrosive nature of some of the reactants and products, such as nitrosyl halide,

HON I-ION it is preferred to conduct the reaction in a reactor fabricated from a material which is inert under the reaction HYdmXamOYl Chloridtt Nitrile Oxide PREPARATION OF O-SULFONATES OF BIS(HYDROXAMOYL CHLORIDES) The product in A or B can be reacted with aromatic diols to give esteroxime O sulfonate polymers which can then be converted to polybenzoxazole (PBO)type polymers in manners analogous to those illustrated above wherein bis(hydroxamoyl halides) have been exemplified as the starting materials.

EXAMPLE 1 To a solution of 23.3 grams (0.1 mol.) ofa bis (hydroxamoyl chlorine) of the formula IION NOH

in 300 mls. of dry cyclohexanone, are added with stirring at room temperature a suspension of 28.0 grams (0.1 mol.) of the dry potassium salt of p,p-dihydroxy diphenyl ether in 200 mls. of cyclohexanone. The addition requires about 30 minutes, after which the reaction mixture is stirred for another 2 hours. the esteroxime polymer is precipitated and washed with hot water .to remove KCl.

The polyesteroxime is dissolved in 300 mls. of pyridine. To this solution are added 41.9 grams (0.22

mols.) of toluene sulfonyl chloride at a temperature of 5C. After standing overnight at 5C, the polybenzoxazole is precipitated, washed and dried.

EXAMPLE 2 POLYBENZOXAZOLES FROM BIS(HYDROXAMOYL CHLORIDES) To a solution of 22.9 grams (0.1 mole) of bisphenol A in 300 ml. of dimethylactemide (DMAc), maintained at C, are added with stirring 23.3 grams (0.1 mole) of bis(hydroxamoyl chloride) of the formula:

The addition is completed in about 20 minutes and stirring is continued 'for another hour at 95C.

To effect ring closure of the esteroxime polymer to form the polybenzoxazole, the reaction mixture is cooled to about 5C. and 38.1 grams (0.2 mole) of toluene sulfonyl chloride and mls. of pyridine are added. The reaction mixture is allowed to stand overnight at 5C., after which water is added and the polymer is filtered, washed with water and methanol, and dried. The washings and filtrate are evaporated for recovery of DMAc and toluene sulfonic acid. (The latter is reconverted to the sulfonyl chloride for reuse by reaction with chlorosulfonic acid.)

EXAMPLE 3 A solution of 16.2 grams (0.05 mol.) of oxydiphenylene-p,p'bis(carbohydroxamoyl chloride), viz.:

NOH (A) in 200 mls. of dry butyrolactone is prepared. To this solution is added with stirring a suspension of the dry sodium derivative of p,p-dihydroxy diphenyl ether 12.3 grams, 0.05 mol.) in 200 mls. of dry butyrolactone. After the addition is complete (20 minutes), the reaction mixture is warmed to 50-60C and stirred at this temperature for another hour. The polyesteroxime is precipitated by addition of water, and is washed and dried.

The polyesteroxime is dissolved in a mixture of 500 mls. DMAc and 300 mls. pyridine. Toluene sulfonyl chloride (19 grams, 0.1 mol.) is added as ring closure reagent, and the mixture is stirred and allowed to stand overnight at 5C. Water is added and the polybenzoxazole is washed'and dried.

The above polyesteroxime also can be prepared by reacting the sodium derivative of p,p'-dihydroxy diphenyl ether with the toluene sulfonate of the bis(hydroxamoyl chloride), viz.

which is made by adding toluene sulfonyl chloride to (A) in the presence of triethylamine.

EXAMPLE 4 To a stirred solution of 10.1 grams (0.05 mol) of p,p-dihydroxy diphenyl ether and 10.1 grams (0.1 mol) tri-ethylamine in 400 ml. tetrahydrofurane, are added 16.2 grams (0.05 mols) of oxydiphenylene-pp" bis( carbohydroxamoyl chloride) of the following structure:

EXAMPLE 5 A solution of 20.0 grams (0.01 mol) of p,p'- dihydroxy diphenyl methane in 400 ml. of N-methyl pyrrolidone is prepared. To this solution 23.2 grams (0.1 mol) of isophthalhydroxamoyl chloride are added with stirring. After about 3 hours of stirring at 60C., the mixture is cooled to 5C. and 38.1 grams (0.2 mol) of toluene sulfonyl chloride are added. The mixture is stirred at 510C. for 12 hours. The polybenzoxazole is filtered, washed and dried.

EXAMPLE 6 5.5 grams (0.05 mol) of m-dihydroxybenzene (resorcinol) are dissolved in 200 ml. of DMAc. A solution in 50 200 ml. of DMAc of 15.4 grams (0.05 mol) of diphenylene bis(carbohydroxamoyl chloride) is added with stirring. This bis(hydroxamoyl chloride) can be prepared by the action of NOCl and Cl, on a mixture of dimethyl diphenyls, as obtained in the o'xidative-coupling 55 of toluene over Pd-i-P, and has the following general structure:

' 65 The reaction mixture 15 stirred at 6070C. for about 3 hours. The mixture is then cooled to 510C., and19 grams (0.1 mol) of toluene sulfonyl chloride are added.

\ Q 60 fwk After standing overnight at 10C., the polybenzoxazole is filtered off, washed and dried.

EXAMPLE 7 PREPARATION OF TEREPI-ITHALBIS(HYDROXAMOYL CHLORIDE) A mixture of nitrosyl chloride and chlorine is generated from conc. nitirc and hydrochloric acids:

HNO 3l-IC1= NOCl Cl, 2H O The NOCl and C1 are passed in gaseous form into a separate glass vessel containing a mixture of p-xylene and sufficinet amounts of carbon tetrachloride, to maintain solubility of reactive intermediates maintained at 15C. An ultraviolet lamp irradiates the reaction mixture for 2-3 hours. The mixture is filtered to remove the crude terephthalbis(hydroxamoyl chloride), which is then recrystallized severaly times from chloroform to yield colorless leaflets melting with decomposition at 188C. The procedure is repeated on the original xy1ene-CCl4 mother liquor with make-up for reacted xylene. Also, by-products from the chloroform mother liquor, such as terephthaldialdoxime, xylylene dichloride, methyl benzaldoxime and methyl benzhydroxamoyl chloride, etc., may be recycled for retreatment.

EXAMPLE 8 Diphenylene-p,p'-(carbohydroxamoyl chloride) is prepared by reaction of NOCl and C1 on p,p'-dimethyl diphenyl. The bis (hydroxamoyl chloride) has the following structure:

15.4 grams (0.05 mol) of this bis(hydroxamoyl chloride) are dissolved in 200 mls. of cyclopentanone. To this solution is added, with stirring, a solution of 9.3 grams (0.05 mol) of dry potassium resorcinolate (mdihydroxy benzene) in 200 mls. of cyclopentanone. The addition is complete in one-half hour. The mixture is stirred for 2 hours at 60C.

The reaction mixture is cooled to 0C, and mls. pyridine and 19.0 grams (0.1 mol) toluenesulfonyl chloride are added with stirring. After standing overnight at 5C, the polybenzoxazole is filtered, washed with water and methanol and dried.

An alternative method is to react (B) with toluenesulfonyl chloride in the presence of an equivalent amount of triethylamine, to form the O-sulfonate prior to reaction with the potassium resorcinolate.

EXPERIMENT 1 PREPARATION OF TEREPI-ITHAL BIS (N-ACETYLATED HYDROXAMOYL CHLORIDE) C Cl Cl The acetylate'd derivative melted at 152C. The elemental analyses were as follows:

Calcd. for C,,H,.,N,O,Cl,: 41.0 3.44 9.56 21.8 24.2 Found: 45.3 3.09 8.69 20.3 23.5

What is claimed is: 1. A process for the preparation of esteroxime polymers which comprises reaction:

A. an alkali metal di-salt of an aromatic dihydroxy compund having the formula:

wherein M is lithium, sodium, or potassium, and Y is wherein X is halogen, OC.;H --OR" or S R" R being alkyl containing up to four carbon atoms); R is a direct bond or a divalent aliphatic radical, a divalent aromatic radical or an organosilicon group selected from the group consisting of (13H: C1 5 Cs s -Si-, Si, and -Si; and X is hydrogen, an SOz0K,

l CH3 C2H 06 5 Lil group, at a temperature of from about 0 to about 250 C. for a period of time sufficient to form the polymer.

2. The process of claim 1 wherein the bis(hydroxamoyl halide) has the formula:

amg HON NOH wherein X is halogen and R is adivalent aliphatic radical, a divalent aromatic radical or an organosilicon group, selected from the group consisting of 3. The process of claim 2 wherein X is bromine or chlorine and R is a divalent aliphatic or aromatic group.

4. The process of claim 3 wherein R is a divalent aliphatic group containing up to about four carbon atoms or a divalent aromatic group containing up to about 18 a carbon atoms.

5. The process of claim 1 wherein the aromatic dihydroxy compound or its alkali metal di-salt contains up to about 30 carbon atoms.

6. The process of claim 1 wherein the aromatic dihydroxy compound or its salt contains up to about 20 carbon atoms.

7. The process of claim 6 wherein there is used a dilithium, disodium or dipotassium salt of the aromatic dihydroxy compound.

8. The process of claim l'wherein an acid-acceptor is present during the reaction.

9. The process of claim 8 wherein the acid-acceptor is melamine, dicyanarnide, or Benzoguanamine.

10. The process of claim 1 wherein there is present during the reaction a solvent selected from the group consisting of acetonitrile, nitromethane, nitrobenzene, methylene chloride, chloroform, carbon tetrachloride, ethylene chloride, chlorobenzene, N,O tetrahydorfurane, diethyl ether, dioxane, amyl acetate, butyrolactone, cyclopentaneone, cyclohexanone, acetic acid. polyphosphoric acid and cresols.

11. The process of'claim 10 wherein the solvent is cyclohexanone.

12. The process of claim 1 wherein there is present 1 14. The process of claim 1 wherein the bis(hydroxamoyl halide) is prepared by reacting a dialkyl aromatic compound with nitrosyl halide for a period of time sufficient to form the product.

15. The process of claim 14 wherein the nitrosyl halide is nitrosyl chloride or nitrosyl bromide.

16. The process of claim 14 wherein the temperature of the reaction is from about 10C. to about 50C.

17. The process of claim 1 wherein the bis(hydroxamoyl halide) is prepared by reacting an aliphatic or aromatic dialdehyde with hydroxylamine to form the corresponding bisoxime, which is then reacted with halogen to form the bis(hydroxamoyl halide), each reaction step being conducted at a temperature of from 0 to 100 C.

18. A film and fiber forming polyesteroxime polymer consisting essentially of repeatings units of the formula:

wherein R is a direct' bond or divalent aliphatic radical, a divalent aromatic radical or an organosilicon group selected from wherein R is 19. The polyesteroxime polymer of claim 18 wherein R is a divalent aliphatic radical containing up to about 20 four carbon atoms.

- 30 about 0 C. to about C. for a period of time sufficient to convert at least some of the esteroxime groups to benzoxazole groups. 

2. The process of claim 1 wherein the bis(hydroxamoyl halide) has the formula:
 3. The process of claim 2 wherein X is bromine or chlorine and R'' is a divalent aliphatic or aromatic group.
 4. The process of claim 3 wherein R'' is a divalent aliphatic group containing up to about four carbon atoms or a divalent aromatic group containing up to about 18 carbon atoms.
 5. The process of claim 1 wherein the aromatic dihydroxy compound or its alkali metal di-salt contains up to about 30 carbon atoms.
 6. The process of claim 1 wherein the aromatic di-hydroxy compound or its salt contains up to about 20 carbon atoms.
 7. The process of claim 6 wherein there is used a dilithium, disodium or dipotassium salt of the aromatic dihyDroxy compound.
 8. The process of claim 1 wherein an acid-acceptor is present during the reaction.
 9. The process of claim 8 wherein the acid-acceptor is melamine, dicyanamide, or Benzoguanamine.
 10. The process of claim 1 wherein there is present during the reaction a solvent selected from the group consisting of acetonitrile, nitromethane, nitrobenzene, methylene chloride, chloroform, carbon tetrachloride, ethylene chloride, chlorobenzene, N2O4, tetrahydorfurane, diethyl ether, dioxane, amyl acetate, butyrolactone, cyclopentaneone, cyclohexanone, acetic acid, polyphosphoric acid and cresols.
 11. The process of claim 10 wherein the solvent is cyclohexanone.
 12. The process of claim 1 wherein there is present during the reaction a solvent which also functions as an acid-acceptor, selected from the group consisting of dimethylacetamide, dimethylformamide, pyrrolidone, N-methylpyrrolidone, dimethyl formamide, dimethyl sulfoxide, hexamethylphosphoramide, and N,N-dimethylaniline.
 13. The process of claim 1 wherein the reaction is conducted at a temperature of from about 0* C. to about 100* C.
 14. The process of claim 1 wherein the bis(hydroxamoyl halide) is prepared by reacting a dialkyl aromatic compound with nitrosyl halide for a period of time sufficient to form the product.
 15. The process of claim 14 wherein the nitrosyl halide is nitrosyl chloride or nitrosyl bromide.
 16. The process of claim 14 wherein the temperature of the reaction is from about -10*C. to about 50*C.
 17. The process of claim 1 wherein the bis(hydroxamoyl halide) is prepared by reacting an aliphatic or aromatic dialdehyde with hydroxylamine to form the corresponding bisoxime, which is then reacted with halogen to form the bis(hydroxamoyl halide), each reaction step being conducted at a temperature of from 0* to 100* C.
 18. A film and fiber forming polyesteroxime polymer consisting essentially of repeatings units of the formula:
 19. The polyesteroxime polymer of claim 18 wherein R'' is a divalent aliphatic radical containing up to about four carbon atoms.
 20. The polyesteroxime polymer of claim 18 wherein R'' is a divalent aromatic radical containing up to about 18 carbon atoms.
 21. The process of claim 1 wherein the esteroxime polymers are contacted with a sulfonyl halide selected from the group consisting of benzene sulfonyl chloride, toluene sulfonyl chloride, naphthalene sulfonyl chloride, or methane sulfonyl chloride at a temperature of about 0* C. to about 90* C. for a period of time sufficient to convert at least some of the esteroxime groups to benzoxazole groups. 